My figure captions numbers are faulty: I have fig. 6.1, 6.2, 6.3, and the next one is 6.5, followed by 6.6 and so on. Say, fig 6.4 number is hiding somewhere.

To keep a figure with its caption (directly underneath) I am placing the figure into a frame, make another frame for the caption just under the figure frame, type the caption there and apply the caption style (shown below). Then I group the two frames to make them to stick together for eternity.

There was a text frame with figure legend containing the skipped number well outside the usually visible spread area. I have searched the whole document at low zoom to see a lot outside the spreads, found the culprit frame ‘stealing’ my figure number and deleted it.